Measuring presbycusis

ABSTRACT

Diagnosing and treating presbycusis (age related hearing loss) includes measuring basilar membrane stiffness. In an example, a low frequency component of an electrocochleogram stimulation signal is used to bias a region of the basilar membrane, the results of which are used basilar membrane stiffness. The resulting measurement is used to measure a subcomponent of presbycusis. Further, the measurement can be combined with known diagnostic methods to reveal or distinguish other origins of hearing loss such as strial presbycusis, sensory presbycusis, neural presbycusis, and cochlea conductive presbycusis. The relative contributions for each of the diagnosed origins of hearing loss can be determined.

BACKGROUND Field of the Invention

The present invention relates generally to the techniques for measuringpresbycusis.

Related Art

Medical devices have provided a wide range of therapeutic benefits torecipients over recent decades. Medical devices can include internal orimplantable components/devices, external or wearable components/devices,or combinations thereof (e.g., a device having an external componentcommunicating with an implantable component). Medical devices, such astraditional hearing aids, partially or fully-implantable hearingprostheses (e.g., bone conduction devices, mechanical stimulators,cochlear implants, etc.), pacemakers, defibrillators, functionalelectrical stimulation devices, and other medical devices, have beensuccessful in performing lifesaving and/or lifestyle enhancementfunctions and/or recipient monitoring for a number of years.

The types of medical devices and the ranges of functions performedthereby have increased over the years. For example, many medicaldevices, sometimes referred to as “implantable medical devices,” nowoften include one or more instruments, apparatus, sensors, processors,controllers or other functional mechanical or electrical components thatare permanently or temporarily implanted in a recipient. Thesefunctional devices are typically used to diagnose, prevent, monitor,treat, or manage a disease/injury or symptom thereof, or to investigate,replace or modify the anatomy or a physiological process. Many of thesefunctional devices utilize power and/or data received from externaldevices that are part of, or operate in conjunction with, implantablecomponents.

SUMMARY

In an example, there is a method comprising: measuring a stiffness of abasilar membrane at a region of a cochlea, wherein the measuringincludes: providing a sound wave having: a first frequency configured toactivate the region; and a second frequency that is lower than the firstfrequency and is configured to bias the region; and measuring a responseto the provided sound wave.

In another example, there is a method comprising: providing a firstsound wave having a first frequency at a first volume to a cochlea;measuring a first response to the first sound wave; providing a secondsound wave to the cochlea such that a measured second response to thesecond sound wave is within a threshold amount of the first response;and determine a stiffness of a basilar membrane of the cochlea based onone or more differences between the first sound wave and the secondsound wave. The second sound wave includes: the first frequency at amodified volume relative to the first volume; and a second frequency,lower than the first frequency, at a second volume.

In yet another example, there is a system comprising: an electroacoustictransducer; a cochlear response sensor; and one or more processors. Theone or more processors are configured to: provide a sound wave using theelectroacoustic transducer and measure a response to the provided soundwave using the cochlear response sensor. The sound wave includes: afirst frequency configured to activate a cochlear region; and a secondfrequency configured to bias the cochlear region.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are described herein in conjunctionwith the accompanying drawings, in which:

FIG. 1 illustrates an example system.

FIG. 2 illustrates an example method.

FIG. 3 illustrates an example sound waves having one frequency providedas input and a resulting output.

FIG. 4 illustrates an example sound waves having first and secondfrequencies provided as input and resulting outputs.

FIG. 5 illustrates a first sound wave, a second sound wave, and a thirdsound wave relative to an activation threshold.

FIG. 6 illustrates first, second, and third sound waves, each havingrespective amplitudes, all relative to an activation threshold.

FIG. 7 illustrates outer hair cell receptor potential over time.

FIG. 8 illustrates outer hair cell receptor potential over time.

FIG. 9 illustrates an example method for measuring a response.

FIG. 10 illustrates one or more processors configured to perform amethod.

FIG. 11 illustrates an example artificial intelligence framework usablewith examples herein.

FIG. 12 illustrates an example cochlear implant system.

FIG. 13 illustrates an example bone conduction device.

DETAILED DESCRIPTION

Typically, causes (“sub-components” or “sub-factors”) of age-relatedhearing loss are bundled together under the term “presbycusis”.Diagnosing and treating the overall rate of decline of hearing can beimproved by measuring the sub-components. While there are at least foursub-factors of presbycusis, each of the four are not typically measuredin humans. The sub-factors include strial presbycusis, sensorypresbycusis, neural presbycusis, and cochlea conductive presbycusis.Strial presbycusis relates to degradation or loss of capillary area andfunction, which can result in reduced endolymphatic potential, loss ofvoltage to the cochlea outer hair cell amplifier. Strial presbycusis isassociated with a hearing loss of approximately 20-60 decibels. Sensorypresbycusis relates to sensory outer hair cell loss (e.g., due to noiseexposure), which can result in reduced outer hair cell amplification dueto loss of outer hair cells. Neural presbycusis relates to spiralganglion neuron degradation or loss of temporal abilities, which canresult in asynchronous firing of the auditory nerve. Cochlea conductivepresbycusis relates to basilar membrane stiffening, which can beassociated with conductive frequency specific loss. Animal research hasbeen used to determine that these sub-factors exist and that they havedifferent contributions to hearing and rates of decline. Strialpresbycusis and sensory presbycusis can be detected based on testingouter hair cell function by measuring otoacoustic emissions or byviewing audiograms (e.g., loss at 2-4 KHz), with some researchsuggesting that strial and sensory presbycusis are separable with deltaauditory brain response compared with delta otoacoustic emissionthreshold. Auditory brainstem response can be used to determine neuralpresbycusis. But there is currently no measure suitable in humans ofbasilar membrane stiffness.

Disclosed techniques include those directed to measuring basilarmembrane stiffness or thickness in vivo. In an example technique, a lowfrequency acoustic tone is used to a constructively or destructivelybias a high frequency tone bust. The ability of the low frequency toneto bias (e.g., move) the basilar membrane is used to measure the basilarmembrane's stiffness. For instance, a relatively stiffer membrane willbe relative less affected by the low frequency compared with arelatively more pliable membrane. An amount to which the low frequencyaffects the region can be used to determine the stiffness of the basilarmembrane at that region. Activation is measured using anelectrocochleogram. The resulting measurement is usable to not onlymeasure stiffness, but also usable in a systemic approach to measureoverall presbycusis and determining the contribution of othersub-factors of presbycusis. The results can be used to improve diagnosisor prediction of hearing loss decline, improved prediction of cochlearimplant outcomes, and tailored hearing aid prescriptions.

Sounds enter the cochlea as a movement in fluid. The basal portion ofthe cochlea is adapted to resonate with high frequencies and is adaptedto resonate with lower frequencies along the cochlea toward the apex ofthe cochlea. As frequencies reach their resonant place, their energy isabsorbed by the basilar membrane. As such, multiple frequencies can bepresent at a same place in the cochlea. The relatively higher frequencycan reach a resonant place where the relatively higher frequencyactivates neurons corresponding to that frequency. Simultaneously, arelatively lower frequency can pass the resonant place of the highfrequency and continue along the cochlea. Although the low frequencydoes not significantly resonate the high frequency region significantly,the low frequency passing through the high frequency region does causesome movement of the basilar membrane. The extent of movement can bemeasured and used to determine presbycusis, such as conductivepresbycusis.

As another example implementation, two tones are provided to the cochleabeing measured. A higher frequency tone activates a specific cochlearegion, and a lower frequency tone biases the region. First, a highfrequency tone is sent at a first level (e.g., volume or intensity)having a moderate response from the cochlea (e.g., sufficient to cause adetectable response). Then, a combination tone that includes highfrequency and low frequency tones are then sent such that the highfrequency component of the tone (e.g., sent as a burst) overlapsconstructively with the low frequency component is then sent in. Whenthe combination is sent, the high frequency component has a reducedlevel (e.g., volume or intensity) relative to the first level. The lowfrequency tone is then increased and decreased to determine the level atwhich the combination tone response is the same level as the single toneresponse. The low frequency level or a ratio between the high frequencyand low frequency level is then used as a measure of the stiffness atthis frequency.

In another implementation, the tone is configured such that the lowfrequency tone destructively overlaps with the high frequency burst. Insuch an implementation, the level of the high frequency component isincreased by an amount (e.g., a 20% volume increase), and the lowfrequency tone would be increased or decreased to find the level wherecombination tone response and the single tone response are similar.

In further implementations, a range of tones are used to determine thestiffness at a range of locations within the cochlea. For a single highfrequency tone, a range of low frequency carriers are used to determinemultiple stiffness measures as, for example, a stiffness spectrogram. Inan example, the measure is conducted at a range of high frequency levels(e.g., intensity or volume) from just above threshold to moderate levelsto loud levels. In an example, multiple constructive (e.g., harmonic)low frequency waves are used to build longer, squarer wave stimulus.

An example system with which example techniques described herein can beimplemented is described in FIG. 1 .

System

FIG. 1 illustrates an examples system 100. The system includes acomputing device 102 being used in relation to a subject's auditoryanatomy, including the outer ear, tympanic membrane, and cochlea. Asillustrated, the cochlea has a first region 10 and a second region whichmay be affected by techniques described herein.

The illustrated computing device 102 includes a stimulator 110, a sensor120, one or more processors 130. Although illustrated as a single device(e.g., the components are disposed in a single housing), the computingdevice 102 can take any of a variety of forms. In an example, thestimulator 110 and sensor 120 are disposed in a housing separate from ahousing encasing the one or more processors 130, with the componentsbeing nonetheless connected via wired or wireless connection. In such anexample, the stimulator 110 and the sensor 120 can be disposed in ahousing configured to be at least partially disposed in or around theperson's auditory anatomy. In an implementation, the one or moreprocessors 130 are of a personal computer, server computer, hand-helddevice, laptop device, multiprocessor system, microprocessor-basedsystem, programmable consumer electronic device (e.g., smart phone ortablet), network personal computer, minicomputer, mainframe computer,other computing devices, or combinations thereof.

The stimulator 110 includes one or more components configured to providestimulation to a subject. In an example, the stimulator 110 isconfigured as an electroacoustic transducer, such as a driver of aheadphone or speaker, that is configured to produce air-conductedvibrations directed to the subject's cochlea so as to set up waves offluid motion of the perilymph within the cochlea that activates the haircells inside of cochlea. In another example, the stimulator 110 is avibratory actuator, such as a transducer of a bone conduction device,that is configured to produce bone-conducted vibrations directed to thesubject's cochlea so as to set up waves of fluid motion of the perilymphwithin the cochlea that activates the hair cells inside of cochlea. Inan example, the stimulator 110 is configured as one or more of anotoacoustic emissions system stimulator, an auditory brainstem responsesystem stimulator, an electrocochleogram system stimulator, adelta-otoacoustic emissions system stimulator, a dual-tone-otoacousticemissions system stimulator, or a multi-tone-otoacoustic emissionssystem stimulator.

The sensor 120 is one or more components configured to generate outputbased on detected conditions. In many examples, the sensor 120 isconfigured to detect otoacoustic emissions, electrocochleographyresponses, other responses, or combinations thereof. In an example, thesensor 120 is a cochlear response sensor configured to detect a responseby a subject's cochlear system. In an example, the sensor 120 includesone or more implanted or external electrodes, such as one or moreimplanted electrodes of a cochlear implant (see, e.g., cochlear implantsystem 1210 of FIG. 12 ). In an example, the sensor 120 includes one ormore of: an otoacoustic emissions sensor, an auditory brainstem responsesensor, an electrocochleogram sensor, electrocochleography monitor, adelta-otoacoustic emissions sensor, or a dual-tone-otoacoustic emissionssensor. In an example, the sensor 120 includes a transtympanic electrode(e.g., an electrode disposed on or configured as a needle for insertionthrough the subject's transtympanic membrane) or a extratympanicelectrode.

The one or more processors 130 are one or more hardware or softwareprocessors (e.g., central processing units or microcontrollers) that areconfigured to obtain and execute instructions. The one or moreprocessors 130 communicate with and control the performance ofcomponents of the computing device 102.

The memory 140 is one or more software- or hardware-basedcomputer-readable storage media operable to store information accessibleby the one or more processors 130. The memory 140 stores, among otherthings, instructions executable by the one or more processors 130 toimplement applications or cause performance of operations describedherein, as well as other data. The memory 140 is implementable asvolatile memory (e.g., RAM), non-volatile memory (e.g., ROM), transitorymemory, non-transitory memory, removable memory, non-removable memory orcombinations thereof. Example implementations of the memory 140 includeRAM, ROM, EEPROM (Electronically-Erasable Programmable Read-OnlyMemory), flash memory, optical disc storage, magnetic storage, solidstate storage, or any other memory media usable to store information forlater access. In some examples, the memory 140 encompasses a modulateddata signal (e.g., a signal that has one or more of its characteristicsset or changed in such a manner as to encode information in the signal),such as a carrier wave or other transport mechanism and includes anyinformation delivery media. Examples include wired media such as a wirednetwork or direct-wired connection, and wireless media such as acoustic,RF, infrared, other wireless media, or combinations thereof. Theillustrated example of the memory 140 stores or encodes one or moreinstructions 142.

The instructions 142 are one or more software instructions executable bythe one or more processors 130 to cause the one or more processors 130to perform one or more actions. The instructions 142 can exist in any ofa variety of forms, such as machine code, a binary executable,interpretable instructions, other forms, or combinations thereof. Insome examples, one or more aspects of the instructions 142 areimplemented in hardware.

The interface 150 encompasses one or more components that enable thecomputing device 102 to interact with one or more users or one or moreother devices.

In an example, the interface 150 includes one or more networkingcomponents that communicatively couple the computing device 102 with oneor more other devices. The networking components provide wired orwireless network access and can support one or more of a variety ofcommunication technologies and protocols, such as ETHERNET, cellular,BLUETOOTH, near-field communication, and RF (Radiofrequency), amongothers. The networking components can include one or more antennas andassociated components configured for wireless communication according toone or more wireless communication technologies and protocols. In anexample, where the stimulator 110 and the sensor 120 are separate fromthe one or more processors 130, one or more networking components areused to communicate between the components. In an example, the interface150 includes one or more input devices over which the input from a useris received. The one or more input devices include physically-actuatableuser-interface elements (e.g., buttons, switches, or dials), touchscreens, keyboards, mice, pens, and voice input devices, among othersinput devices. In an example, the interface 150 includes one or moreoutput devices by which the computing device 102 provides output to auser, such as one or more displays, speakers, and printers, among otheroutput devices.

In an example, the computing device 102 includes one or more componentsconfigured to operate as one or more of an otoacoustic emissions system(e.g., a distortion product otoacoustic emission), an auditory brainstemresponse system, an electrocochleogram system, a delta-otoacousticemissions system, or a dual-tone-otoacoustic emissions system. Examplecomponents for operating an electrocochleography system are described inUS 2017/0304632, which is titled “Electrocochleography Testing inHearing Prostheses”, and which is hereby incorporated herein byreference in its entirety for any and all purposes.

The components of the system 100 are usable to perform one or moremethods or operations, including those described in relation to FIGS. 2,9, and 10 .

Example Method

FIG. 2 illustrates an example method 200 that includes measuring astiffness of a basilar membrane, diagnosing a hearing condition, andperforming a treatment action. The method 200 can begin with operation210.

Operation 210 includes measuring stiffness of a basilar membrane at afirst region 10 of a subject's cochlea. The operation 210 can includeone or more sub-operations. The illustrated operation 210 includesoperations 220, 230, 234, 240, 250, 254, and 256. Other implementationscan include more, fewer, or different operations. The measuring of thestiffness can be repeated for one or more additional regions of thecochlea.

Operation 220 includes providing a first sound wave 222 to the cochlea,such as via the stimulator 110. The illustrated example of the firstsound wave 222 includes a first frequency 224 that has a first volume226. The first sound wave 222 is provided in any of a variety of ways,such as via a receiver, a speaker, a headphone, or a vibratory actuator.In an example, the first volume 226 is a volume above an otoacousticemission threshold. The otoacoustic emission threshold can be an actualthreshold or predicted threshold (e.g., based on typical responses fromsimilar individuals) for the subject that, when satisfied, causes anotoacoustic emission.

In an example, the first sound wave 222 is an initial sound wave used togather initial data regarding a first region 10 of the subject'scochlea. The first region 10 can also be referred to as the targetregion 10 or the tested region 10 and refers to the region of thesubject's cochlea (e.g., the region of the basilar membrane of thecochlea) that resonates (or is believed to resonate) with the firstfrequency 224.

Operation 230 includes measuring a first response 232, such as via thesensor 120. The first response 232 is a response to the first sound wave222. In an example, the first response 232 is a detected otoacousticemission produced by the subject's cochlea in response to the firstsound wave 222. The first response 232 can be a direct or indirectmeasurement of the subject's outer hair cell receptor potential orfiring of spiral ganglion neurons. In some examples, the first response232 is measured using evoked compound action potential orelectrocochleography. Additional techniques for measuring a response aredescribed in relation to FIG. 9 . In some examples, the first response232 is used as a baseline against which subsequent responses aremeasured. A non-limiting example of providing a sound wave and receivinga response is shown in FIG. 3 .

FIG. 3 illustrates an example of providing input to a subject's auditorysystem and detecting a response. As illustrated, a first sound wave 302results in receiving a slightly delayed first signal 303 and a secondsound wave 304 results in receiving a slightly delayed second signal305. In an example, the first sound wave 302 and the second sound wave304 are provided in the form of air- or bone-conducted vibrations andthe first signal 303 and the second signal 305 are received asotoacoustic emissions detected by a microphone. In other examples, thefirst signal 303 and the second signal 305 are detected as electricalsignals, such as detected by an electrode.

Returning to FIG. 2 , operation 234 includes selecting a second soundwave 242, such as using the one or more processors 130. The illustratedexample of the second sound wave 242 includes the first frequency 224 ata modified volume 245, a second frequency 246 at a second volume 247,and one or more optional, additional frequencies 248.

The first frequency 224 of the second sound wave 242 is selected to besubstantially the same as the first frequency 224 of the first soundwave 222. In an example, the first frequency 224 is within a margin oferror or tolerance of the stimulator 110 being used to generate thesound waves 222, 242. Generally, the first frequency 224 of the secondsound wave 242 is configured to stimulate the first region 10, which isthe same region of the subject's cochlea stimulated by the first soundwave 222.

The volume of the first frequency 224 is selected to be the same as ordifferent from the first volume 226. As illustrated, the volume of thefirst frequency 224 is a modified volume 245. The modified volume 245 ismodified relative to the first volume 226, such as by being higher orlower than the first volume 226. In an example, the modified volume 245is selected to be above an otoacoustic emission threshold (an actual orassumed otoacoustic emission threshold for the subject). In an example,the modified volume 245 is more than 5%, 10%, 15%, 20%, 25%, 30%, 35%,40%, 45%, or 50% different (e.g., higher or lower) compared to the firstvolume 226. In at least some examples, the modified volume 245 isselected to be a volume that will result in a response to the secondsound wave 242 being substantially the same as a response 232 to thefirst sound wave 222, such as is described in more detail below. Inother examples, the first frequency 224 has a volume that issubstantially the same as the first volume 226 (e.g., within a toleranceor margin of error of the stimulator 110 that produced the second soundwave).

The second frequency 246 is a frequency configured to bias the firstregion 10 of the cochlea. In an example, the second frequency 246 isselected to be a frequency that is lower than the first frequency 224.For instance, the second frequency 246 is a frequency that is configuredto resonate a second region 20 of the cochlea different from the firstregion 10, yet still affect the first region 10 such that the secondfrequency 246 constructively or destructively biases the first region10. In an example, the operation 234 includes selecting the second soundwave 242 such that a measured second response (see operation 250, below)to the second sound wave 242 is within a threshold amount of the firstresponse 232. In an example, the second frequency 246 is configured toconstructively bias the first region 10, and in another example, thesecond frequency 246 is configured to destructively bias the firstregion 10. In an example, the second volume 247 is selected to be belowan actual or believed otoacoustic emission threshold for the subject.

In some examples, the second frequency 246 is selected to have one ormore additional frequencies 248 having their own volumes or volumessimilar to the second volume 247 or modified volume 245. In an example,the one or more additional frequencies 248 are selected. In an example,the one or more additional frequencies 248 are harmonic. In an example,the one or more additional frequencies 248 are selected to contribute toa substantially square wave shape of the second sound wave 242, such asa square wave shape over which the first frequency 224 is provided as aburst.

Operation 240 includes providing the second sound wave 242, such as viathe stimulator 110. In examples, the second sound wave 242 is generatedsuch that the first frequency 224 is provided as a short burst at aparticular portion of the second frequency 246, rather than beingsubstantially continuous for the duration of the second sound wave 242.For instance, the first frequency can be a burst proximate the crest ortrough of the second frequency 246 component of the second sound wave242, such that the second frequency 246 provides constructive ordestructive bias, respectively, during the time at which the firstfrequency 224 resonates the first region 10.

In an example, the second sound wave 242 is provided to the cochlea suchthat a measured second response (see operation 250) to the second soundwave 242 is within a threshold amount of the first response 232. In someexamples, an initial providing of the second sound wave 242 results insuch a measured second response 252. In other examples, the initialproviding of the second sound wave 242 does not result in such ameasured second response 252. The second sound wave 242 can be modifieduntil a measured second response 252 is achieved that is within athreshold amount of the first response 232. Such a modification isdescribed in relation to operation 254, below.

Operation 250 includes measuring a second response 252. The secondresponse 252 is a response to the provided second sound wave 242. In anexample, the second response 252 is measured in substantially the sameway as the first response 232. In another example, the second response252 is measured such in such a way that the second response 252 includesthe subject's response to the first frequency 224 component of thesecond sound wave 242 but not the second frequency 246 component. Such atechnique is described in more detail in relation to FIG. 3 . In someexamples, the second response 252 includes a component relating to aresponse to the first frequency 224 and a component relating to aresponse to the second frequency 246.

Operation 254 includes modifying the second sound wave 242. For example,the operation includes modifying the second sound wave 242 until ameasured second response 252 to the second sound wave 242 is within thethreshold amount of the first response 232. Example modificationsinclude modifying the modified volume 245 of the first frequency 224 ormodifying the second volume 247 of the second frequency 246. Forinstance, responsive to the second response 252 being lower (e.g., lessintense) than the first response 232, the modified volume 245 isincreased. Responsive to the second response 252 being higher (e.g.,more intense) than the first response 232, the modified volume 245 isdecreased. Following the modifying of the second sound wave 242, themodified second sound wave 242 can be provided, with the flow of themethod 400 returning to operation 240.

A non-limiting example of a second sound wave 242 and second responses252 thereto are shown in FIG. 4 .

FIG. 4 illustrates an example sound wave 410 provided as input and aresulting output. The sound wave 410 includes a first frequencycomponent 412 having a relatively higher frequency than a secondfrequency 414 component. As illustrated, the sound wave 410 includesfirst frequency section A 416 and first frequency section B 418proximate a crest and a trough of the second frequency 414 component ofthe sound wave 410, respectively. As illustrated, the first frequencysection A 416 and first frequency section B 418 are configured ashigh-frequency bursts over particular portions of the second frequency414 component.

As illustrated, the second frequency component 414 results insubstantially no detectable output from the subject. The first frequencysection A 416 results in a first output section 420 having a relativelyhigher amplitude than the second section output section 430 resultingfrom the first frequency section B 418. The first frequency section A416 is proximate a crest of the second frequency component 414, whichresults in the crest of the second frequency component 414 providing aconstructive bias to the first region 10 (e.g., the region that thefirst frequency section A 416 resonates with) and therefore results in ahigher amplitude of output in the first output section 420. The firstfrequency section B 418 proximate a trough of the second frequencycomponent 414 results in a destructive bias to the first region 10 andtherefore results in a lower amplitude of output in the second outputsection 430.

Continued examples of combinations of high and low frequencies are shownin FIGS. 5 and 6 .

FIG. 5 illustrates a first sound wave 510, a second sound wave 520, anda third sound wave 530 relative to an activation threshold 502. Thefirst sound wave 510 is similar to the sound wave 410 of FIG. 4 andincludes a high frequency section located at a crest of a low frequencysection, thereby being constructively biased. The first sound wave 510includes a first amplitude 512. The second sound wave 520 includes anunbiased high frequency section having a second amplitude 522 sufficientto cause the second sound wave 520 to reach the activation threshold502. The third sound wave 530 includes an unbiased high frequencysection having a third amplitude 532. The first amplitude 512 and thethird amplitude 532 are substantially similar and approximately half ofthe second amplitude 522. As illustrated, the constructive bias of thefirst sound wave 510 is sufficient to cause the sound wave 510 to reachthe activation threshold 502 despite the first amplitude 512 beingapproximately half of the second amplitude 522. The third sound wave 530has approximately the same amplitude as the first sound wave 510 but isunbiased and is therefore unable to reach the activation threshold.

FIG. 6 illustrates a first sound wave 610 having a first amplitude 612,a second sound wave 620 having a high frequency section having a secondamplitude 622, and a third sound wave 630 having a high frequencysection having a third amplitude 632, all relative to and reaching anactivation threshold 602.

The first sound wave 610 is unbiased and reaches the activationthreshold 602. The second sound wave 620 includes a low-frequencysection that constructively biases the high frequency section in such away that the high-frequency section reaches the activation threshold 602despite the second amplitude 622 being substantially half of the firstamplitude 612. The third sound wave 630 includes a low-frequency sectionthat destructively biases the high frequency section in such a way thatthe high-frequency section reaches the activation threshold 602 with thethird amplitude 632 being substantially double the first amplitude 612.

In some examples, the response from the subject's auditory system is oris related to the firing of the subject's Spiral Ganglion (SPG). Thesound waves provided to the auditory system can affect the voltagepotential of the recipient's outer hair cells. Where the voltagepotential reaches a certain threshold, the SPG fires. An example of thisprocess is shown in FIGS. 7 and 8 .

FIG. 7 illustrates outer hair cell receptor potential over time inresponse to an input signal (e.g., a sound wave). The outer hair cellreceptor potential is approximately centered around −50 mV and shiftspotential between approximately −60 mV and −40 mV as a result of theinput signal. When the receptor potential is approximately −40 mV, theSPG neuron fires shortly after. In some examples, this firing isdetected as the response 232, 252.

FIG. 8 illustrates outer hair cell receptor potential over time inresponse to an input signal. The potential is approximately centeredaround −55 mV due to being destructively biased (e.g., as a result of ahigh frequency burst being provided over a trough of a low frequency),resulting in shifts in potential of between approximately −65 mV and −45mV. Because the receptor potential is less than approximately-40 mV,there is no firing of SPG neurons.

Returning to FIG. 2 , operation 256 includes determining stiffness 258.In an example, determining the stiffness 258 includes determining astiffness 258 of a basilar membrane of the cochlea (e.g., the stiffnessof the first region 10) based on one or more differences between thefirst sound wave 222 and the second sound wave 242. In many examples,the stiffness 258 is derived from an extent to which the secondfrequency 246 component of the second sound wave 242 biased the membraneat the first region 10. This extent is determinable based on thedifferences between the second response 252 (which was in response to asound wave 242 that had the biasing second frequency 246) and the firstresponse 232 (which was in response to the first sound wave 222 thatlacked the biasing second frequency 246). The difference can bedetermined based on or expressed as a ratio between the first volume 226and the modified volume 245, where the modified volume 245 is a volumeneeded to overcome the bias to result in substantially similar first andsecond responses 232, 252. In another example, the stiffness 258 ismeasured as the ratio of input signal (dB) to electrical neural response(uV), where the input signal corresponds to the modified volume 245 andthe electrical neural response corresponds to the second response 252.

In an example, determining the stiffness 258 includes providing data toan artificial intelligence framework (e.g., as described in FIG. 11 )and receiving an output in response that indicates the value ofstiffness 258. The data provided to the artificial intelligenceframework can include data describing the first sound wave 222 and thesecond sound wave 242, such as the first frequency 224, the first volume226, the modified volume 245, the second volume 247, and data regardingone or more additional frequencies 248. The artificial intelligenceframework can be trained to receive such data as input and provide astiffness measure as output.

In an example, the stiffness 258 is a measure of the first region 10 ofthe cochlea. In another example, the stiffness 258 is an actual orestimated measurement of the stiffness of the subject's cochlea overall.For instance, the stiffness 258 may be a value generated based on anaverage or other statistical process applied to one or more otherobtained stiffnesses 258.

Operation 260 includes diagnosing a hearing condition. In examples thediagnosing includes diagnosing the extent of the hearing condition(e.g., an amount of hearing loss). In an example, the hearing conditionis diagnosed based on the stiffness 258 of the basilar membrane beingabove a diagnostic threshold. In some examples, the diagnosing caninclude one or more of operations 262, 264, and 266.

Operation 262 includes determining a level of cochlea conductivepresbycusis. The level is determined based on the measured secondresponse 252. Cochlea conductive presbycusis relates to basilar membranestiffening, thus measures related to stiffness are usable to determine alevel of cochlea conductive presbycusis. For example, the level ofcochlea conductive presbycusis is determined based on the stiffness 258as calculated based on the measured second response 252. The determiningcan be performed in any of a variety of ways. In some examples, thedetermining is based on one or more equations that take at least thestiffness 258 as a variable and produce, as an output, a level ofcochlea conductive presbycusis. In some examples, the determining isbased on a lookup table, where levels of cochlea conductive presbycusisare indexed to measures of stiffness 258. In some examples, anartificial intelligence technique is used to determine the level ofcochlea conductive presbycusis, such as by providing the stiffness 258as input to an artificial intelligence framework and receiving, asoutput, the determined level of cochlea conductive presbycusis.

In addition to or instead of determining the level of cochlea conductivepresbycusis, the method 200 determines a level of overall presbycusis.The level of overall presbycusis can be determined based on contributingfactors to the overall presbycusis. For instance, the following equationcan be used:

Presbycusis(dB HL)=Y*Strial+Φ*Sensory+X*Neural+Π*Conductive,

where the input variables Strial, Sensory, Neural and Conductiverepresent the measure of their respective presbycusis subfactor. Forexample, Conductive can, in one example, correspond to the measure ofthe stiffness of the basilar membrane represented in the ratio betweenthe first volume 226 and the modified volume 245. In an example, Neuralcan correspond to the measure of the auditory brainstem response. Inthis example linear multi-regression model, the coefficients Y, Φ, X,and Π can be determined, through calculation or experimentation, toprovide the estimate of the Presbycusis through the input variables. Forexample, if the patient had Presbycusis which was solely due toconductive presbycusis (stiffening of the basilar membrane), then theStrial, Sensory and Neural variables would not contribute to the model,and the resultant Presbycusis would be a function of Π*Conductive. Avariety of techniques can be used to determine the values of Y, Φ, X,and Π. Examples are described below in relation to operations 264 and266. And similarly, a variety of techniques or transforms can be used todetermine Strial, Sensory, Neural, and Conductive, to provide a linearvariable type for this simple variable model.

Operation 264 includes determining a plurality of presbycusissub-factors, such as a level of the plurality of sub-factors. In anexample, the presbycusis sub-factors include strial presbycusis, sensorypresbycusis, neural presbycusis, and cochlea conductive presbycusis.Other sub-factors can be used. Levels of strial presbycusis and sensorypresbycusis are determined based on testing outer hair cell function,such as by measuring otoacoustic emissions or through the use ofaudiograms (e.g., as evidenced by loss at 2-4 KHz). The relativecontribution of strial and sensory presbycusis is determinable based ondelta auditory brain response compared with delta otoacoustic emissionthreshold. Auditory brainstem response can be used to determine neuralpresbycusis. The cochlea conductive presbycusis is determined using oneor more of the techniques described in operation 262. In an example,otoacoustic emissions, auditory brainstem response, and the determinedstiffness are used to determine the values of Y, Φ, X, and Π.

Operation 266 includes determining contribution of each of the pluralityof presbycusis sub-factors to overall presbycusis. With the plurality ofpresbycusis sub-factors determined in operation 264, the relativecontribution of each factor is determined. For example, the extent towhich each factor contributes to overall presbycusis is determined.

Operation 270 includes performing a treatment action 272. The treatmentaction 272 can be determined based on the measured plurality ofpresbycusis sub-factors of operation 264. Example treatment actions 272include recommending a pharmacological substance, recommending a hearingaid, recommending a bone conduction device, recommending a cochlearimplant, recommending a hearing aid fitting, recommending a boneconduction fitting, other recommendations, or combinations thereof.

In an example, responsive to determining that an amount of sensorypresbycusis is above a predetermined threshold, a hearing aid isprescribed as the treatment action 272. In an example, responsive todetermining that an amount of strial presbycusis is above apredetermined threshold, a voltage pump or vascular dilation drug can beprescribed as the treatment action 272. In an example, responsive todetermining that an amount of inner hair cell loss, the prescription ofDNA therapy can be prescribed or recommended as the treatment action.

In an example, responsive to determining that a level of overallpresbycusis or levels of one or more sub-factors passes a threshold, asubject that is already a recipient of an auditory prosthesis, isrecommended one or more changes in settings to address the presbycusis.For example, the level of overall presbycusis indicates that therecipient is losing residual hearing and the treatment action 272 is tochange one or more settings of an existing auditory prosthesis.

As described above, various techniques can be used to measure a response(e.g., the first response 232 and the second response 252). Additionaltechniques for measuring a response are described in relation to FIG. 9.

Measuring a Response

FIG. 9 illustrates a method for measuring a response 902. Measuring theresponse 902 can include measuring one or more of auditory brainstemresponse, an electrocochleogram, and electrical compound actionpotentials, such as with the sensor 130. In an example, the response ismeasured with one or more electrodes of a cochlear implant or atrans-tympanic electrode. In an example, the response is measured with amicrophone.

The method 902 includes operation 910, which includes measuringotoacoustic emissions. The otoacoustic emissions can includedelta-otoacoustic emissions or dual-tone-otoacoustic emissions.

In some examples, the otoacoustic emissions are measured in response tothe second sound wave 242 that includes the first frequency 224 and thesecond frequency 246. In many examples, the second frequency 246 is usedto bias the first region 10 of the cochlea where the first frequency 224resonates. The second frequency 246 resonates with the second region 20of the cochlea that is different from the first region 10. Thus, whilethe second frequency 246 may result in generating an otoacousticemission or other response by resonating with the second region 20 ofthe subject's auditory system, the response may not be relevant todetermining qualities of the first region 10 of the cochlea where thefirst frequency 224 resonates. As a result, in some examples, the secondfrequency 246 of the second sound wave 242 is configured to affect thetarget region of the subject's cochlea while nonetheless being below anotoacoustic emissions threshold. In other examples, the second frequency246 of the second sound wave 242 is sufficient to cause otoacousticemissions, but the response provoked by the second frequency 246 isdisregarded. The operations are operations 912, 914, and 916.

Operation 912 includes receiving a first otoacoustic emission. The firstotoacoustic emission corresponds to the first frequency 224 component ofthe second sound wave 242. Because the first frequency 224 is higherthan the second frequency 246, the first frequency 224 resonates at amore basal location of the cochlea. Resonating at the more basal firstregion 10 results in the otoacoustic emission corresponding to the firstfrequency 224 being produced first.

Operation 914 includes receiving a second otoacoustic emission. Thesecond otoacoustic emission can correspond to the second frequency 246component of the second sound wave 242. Because the second frequency 246is lower than the first frequency 224, the second frequency 246resonates at a more apical location of the cochlea. Resonating at themore apical second region 20 results in the otoacoustic emissioncorresponding to the second frequency 246 being produced after the firstotoacoustic emission. Thus, the timing of receipt of the otoacousticemissions can be used to distinguish them as relating to the firstfrequency 224 or the second frequency 246. In other examples, theemissions are distinguished via other techniques, such as based on othercharacteristics of the responses.

Operation 916 includes disregarding the second otoacoustic emission. Thedisregarding can be performed in any of a variety of ways. For instance,the second otoacoustic emission is received but not saved or stored forlater use. As another example, the sensor 120 that receives theotoacoustic emission is turned off or otherwise configured to notgenerate output based on the second otoacoustic emission. In a stillfurther example, data is generated based on the second otoacousticemission but the data is flagged or otherwise distinguished as beingrelated to the second otoacoustic emission such that the data relatingto the second otoacoustic emission is not used.

Measuring a Response

FIG. 10 illustrates one or more processors 130 configured to perform amethod 1000 that includes various operations. The one or more processors130 can be communicatively coupled to memory 140 having stored thereoninstructions that so configure the one or more processors 130. Forinstance, the memory 140 can include instructions 142 thereon that, whenexecuted by the one or more processors 130, cause the one or moreprocessors 130 to perform the one or more operations herein. In anexample, the operations include operation 1010, operation 1020, 1030,1040, 1050, 1060, and 1070.

Operation 1010 includes to provide a sound wave 1002. As illustrated,the sound wave 1002 includes a first frequency 224 at a first volume1004, a second frequency 246 at a second volume 247, and an additionalfrequency 248. In an example, the operation 1010 can include one or moreaspects of those described in relation to operation 240. In someexamples, operation 1010 includes operations 1012 and 1014.

Operation 1012 includes to select the first frequency 224. In anexample, the operation 1012 includes selecting a first frequencyconfigured to activate the first region 10. For example, a target regionof the subject's cochlea is chosen (e.g., based on a diagnostic plan orsymptoms of the subject) as the first region 10 and the first frequency224 is selected to target the first region 10 based on the ability ofthe first frequency 224 to resonate at the first region 10. In someexamples, the operation 1012 further includes to select the first volume1004 of the first frequency 224. In an example, the first volume 1004corresponds to the modified volume 245 of the second sound wave 242 ofFIG. 2 and can be selected in a similar manner. In an example, theoperation 1012 can include one or more aspects of those described inrelation to operation 234 and 254.

Operation 1014 includes to select a second frequency 246. In an example,the operation 1014 includes selecting a second frequency 246 configuredto bias the first region 10, such as constructively bias ordestructively bias the first region 10. In an example, the operation1014 can include one or more aspects of those described in relation tooperation 234 and 254.

Operation 1020 includes to measure a response 1022. The response 1022 isto the provided sound wave 1002. In an example, the operation 1020includes one or more aspects similar to those described in relation tooperation 250.

Operation 1030 includes to provide a stiffness measurement. Thestiffness measurement can be a measurement of the stiffness of the firstregion 10 and can be based on the response 1022. In an example, thestiffness is determined using one or more techniques described inrelation to operation 256. The stiffness measurement can then beprovided to the subject or a clinician using any of a variety oftechniques, such as by displaying the result on a display screen or byaudibly providing the stiffness measurement

Operation 1040 includes to determine multiple stiffness measurements.For instance, at least operations 1010, 1020, and 1030 are repeated formultiple different values of the first frequency 224 to determine themultiple stiffness measurements for different regions in the subject'scochlea. In an example, the multiple stiffness measurements are a rangeof frequencies lower than the original first frequency 224 used todetermine the original stiffness measurement before the operations arerepeated. The multiple stiffness measurements can be used to determinean overall stiffness of the basilar membrane of the subject's cochlea(e.g., based on averaging or performing another statistical process onthe multiple stiffness measurements).

Operation 1050 includes to provide multiple stiffness measures as astiffness spectrogram. For example, the multiple stiffness measurementsobtained in operation 1040 can be provided to a user (e.g., the subjector a clinician). In an implementation, the x-axis of the spectrogramcorresponds to frequency and the y-axis of the spectrogram correspondsto stiffness.

Operation 1060 includes to determine presbycusis. For example, thepresbycusis can include cochlea conductive presbycusis and can bedetermined based on the response 1022. In addition, the presbycusis caninclude strial presbycusis, sensory presbycusis, and neural presbycusis.The operation 1060 can include one or more aspects similar to thosedescribed above in relation to operation 260.

Operation 1070 includes to recommend a treatment action 272. Forexample, the operation 1070 can include one or more aspects similar tothose described in relation to operation 270.

Example Artificial Intelligence Model

FIG. 11 illustrates an example artificial intelligence framework 1100usable with examples herein. In an example, the computing device 102stores and operates the artificial intelligence framework 1100. Theartificial intelligence framework 1100 includes software instructionsand associated data that implement artificial intelligence capabilities.

In examples, the artificial intelligence framework 1100 definesimplementations of one or more different artificial intelligencetechniques. For example, the artificial intelligence framework 1100defines a decision tree (e.g., the nodes of the decision tree and theconnections therebetween).

In the illustrated example, the artificial intelligence framework 1100includes a machine-learning model 1110 and a machine-learning interface1120. One or more aspects of the artificial intelligence framework 1100can be implemented with machine-learning toolkits or libraries, such as:TENSORFLOW by GOOGLE INC. of Mountain View, California; OPENAI GYM byOPENAI of San Francisco, California; or MICROSOFT AZURE MACHINE LEARNINGby MICROSOFT CORP. of Redmond, Washington.

The machine-learning model 1110 is a structured representation of thelearning, such as how learning is achieved and what has been learned.For example, where the machine-learning model 1110 includes a neuralnetwork, the machine-learning model 1110 can define the representationof the neural network (e.g., the nodes of the neural network, theconnections between the nodes, the associated weighs, and other data),such as via one or more matrices or other data structures.

The machine-learning interface 1120 defines a software interface used inconjunction with the machine-learning model 1110. For example, themachine-learning interface 1120 can define functions, processes, andinterfaces for providing input to, receiving output from, training, andmaintaining the machine-learning model 1110.

In some examples, the machine-learning interface 1120 requires the inputdata to be preprocessed. In other examples, the machine-learninginterface 1120 can be configured to perform the preprocessing. Thepreprocessing can include, for example, placing the input data into aparticular format for use by the machine-learning model 1110. Forinstance the machine-learning model 1110 can be configured to processinput data in a vector format and the data provided for processing canbe converted into such a format via the preprocessing. In an example,the interface provides functions that convert the provided data into auseful format and then provide the converted data as input into themachine-learning model 1110.

The machine-learning interface 1120 can define a training procedure 1130for preparing the machine-learning model 1110 for use. The artificialintelligence framework 1100 can be trained or otherwise configured toreceive data as input and provide an output based thereon. For example,the machine-learning model 1110 can be trained to receive data orparameters described herein as input and provide, as output, anindication of whether the provided data is indicative of an amount ofstiffness or an extent of presbycusis. The training procedure 1130 canbegin with operation 1132.

Operation 1132 includes obtaining training data. The training data istypically a set of human- or machine-curated data having known traininginput and desired training output usable to train the machine-learningmodel 1110. In examples herein, the training data can include curatedresponses 1022 from many different individuals or that isartificially-created and actual or expected output of themachine-learning model 1110 for that data. For example, the trainingdata can include particular responses 1022 associated with measurementsof stiffness. Following operation 1132, the flow can move to operation1134.

Operation 1134 includes processing the training data. Processing thetraining data includes providing the training data as input into themachine-learning model 1110. In examples, the training data can beprovided as input into the machine-learning model 1110 using anassociated machine-learning interface 1120. Then the machine-learningmodel 1110 processes the input training data to produce an output.

Following operation 1134, the flow can move to operation 1136. Operation1136 includes obtaining the output from the machine-learning model 1110.This can include receiving output from a function that uses themachine-learning model 1110 to process input data. Following operation1136, the flow can move to operation 1138.

Operation 1138 includes calculating a loss value. A loss function can beused to calculate the loss value, such as based on a comparison betweenthe actual output of the machine-learning model 1110 and the expectedoutput (e.g., the training output that corresponds to the training inputprovided). Any of a variety of loss functions can be selected and used,such as mean square error or hinge loss. Attributes of themachine-learning model 1110 (e.g., weights of connections in themachine-learning model) can be modified based on the loss value, therebytraining the model.

If the loss value is not sufficiently small (e.g., does not satisfy athreshold), then the flow can return to operation 1132 to further trainthe machine-learning model 1110. This training process continues for anamount of training data until the loss value is sufficiently small. Ifthe loss value is sufficiently small (e.g., less than or equal to apredetermined threshold), the flow can move to operation 1140.

Operation 1140 includes completing the training. In some examples,completing the training includes providing the artificial intelligenceframework 1100 for use in production. For example, the artificialintelligence framework 1100 with the trained machine-learning model 1110can be stored on the computing device 102 or at another location foruse. In some examples, prior to providing the artificial intelligenceframework 1100 for use, the trained machine-learning model 1110 isvalidated using validation input-output data (e.g., data having desiredoutputs corresponding to particular inputs that are different from thetraining data), and after successful validation, the artificialintelligence framework 1100 is provided for use.

The machine-learning model 1110 can include multiple different types ofmachine-learning techniques. For example, the machine-learning model1110 can define multiple different neural networks, decision trees, andother machine-learning techniques and their connections therebetween.For instance, output of a first neural network can flow to the input ofa second neural network with the output therefrom flowing into adecision tree to produce a final output.

Example Devices

Technology described herein can result in the subject of the test beingprescribed a device, such as a cochlear implant, an electroacousticdevice, a percutaneous bone conduction device, a passive transcutaneousbone conduction device, an active transcutaneous bone conduction device,a middle ear device, a totally-implantable auditory device, amostly-implantable auditory device, an auditory brainstem implantdevice, a hearing aid, a tooth-anchored hearing device, other auditoryprostheses, and combinations of the foregoing (e.g., binaural systemsthat include a prosthesis for a first ear of a recipient and aprosthesis of a same or different type for the second ear). In someexamples, techniques described herein can be relevant to consumerdevices, such as a personal sound amplification product. Further, insome examples, such devices can be used to stimulate and record theresponses. Further still, a subject of the tests described herein may bea recipient of such devices and techniques used herein are used todetermine presbycusis of residual hearing. In still further examples,stiffness and amount of presbycusis can be used to modify stimulationsettings of such devices.

Among the devices are cochlear implant systems, which are described inmore detail in relation to FIG. 12 , below, and bone conduction devices,which are described in more detail in relation to FIG. 13 , below.

Example Device—Cochlear Implant

FIG. 12 illustrates an example cochlear implant system 1210 that can beused with examples herein. For example, the cochlear implant system 1210can be used to implement the computing device 102 or one or both of thestimulator 110 and the sensor 120. The cochlear implant system 1210includes an implantable component 1244 typically having an internalreceiver/transceiver unit 1232, a stimulator unit 1220, and an elongatelead 1218. The internal receiver/transceiver unit 1232 permits thecochlear implant system 1210 to receive signals from and/or transmitsignals to an external device 1250. The external device 1250 can be abutton sound processor worn on the head that includes areceiver/transceiver coil 1230 and sound processing components.Alternatively, the external device 1250 can be just atransmitter/transceiver coil in communication with a behind-the-eardevice that includes the sound processing components and microphone.

The implantable component 1244 includes an internal coil 1236, andpreferably, an implanted magnet fixed relative to the internal coil1236. The magnet can be embedded in a pliable silicone or otherbiocompatible encapsulant, along with the internal coil 1236. Signalssent generally correspond to external sound 1213. The internalreceiver/transceiver unit 1232 and the stimulator unit 1220 arehermetically sealed within a biocompatible housing, sometimescollectively referred to as a stimulator/receiver unit. Included magnetscan facilitate the operational alignment of an external coil 1230 andthe internal coil 1236 (e.g., via a magnetic connection), enabling theinternal coil 1236 to receive power and stimulation data from theexternal coil 1230. The external coil 1230 is contained within anexternal portion. The elongate lead 1218 has a proximal end connected tothe stimulator unit 1220, and a distal end 1246 implanted in a cochlea1240 of the recipient. The elongate lead 1218 extends from stimulatorunit 1220 to the cochlea 1240 through a mastoid bone 1219 of therecipient. The elongate lead 1218 is used to provide electricalstimulation to the cochlea 1240 based on the stimulation data. Thestimulation data can be created based on the external sound 1213 usingthe sound processing components and based on sensory prosthesissettings.

In certain examples, the external coil 1230 transmits electrical signals(e.g., power and stimulation data) to the internal coil 1236 via a radiofrequency (RF) link. The internal coil 1236 is typically a wire antennacoil having multiple turns of electrically insulated single-strand ormulti-strand platinum or gold wire. The electrical insulation of theinternal coil 1236 can be provided by a flexible silicone molding.Various types of energy transfer, such as infrared (IR),electromagnetic, capacitive and inductive transfer, can be used totransfer the power and/or data from external device to cochlear implant.While the above description has described internal and external coilsbeing formed from insulated wire, in many cases, the internal and/orexternal coils can be implemented via electrically conductive traces.

Example Device—Bone Conduction Device

FIG. 13 is a view of an example of a bone conduction device 1300 thatcan benefit from use of the technologies disclosed herein. For example,the bone conduction device 1300 can be used to implement the computingdevice 102 or one or both of the stimulator 110 and the sensor 120. Thebone conduction device 1300 is positioned behind an outer ear 1301 of arecipient of the device. The bone conduction device 1300 includes asound input element 1326 to receive sound signals 1307. The sound inputelement 1326 can be a microphone, telecoil or similar. In the presentexample, the sound input element 1326 is located, for example, on or inthe bone conduction device 1300, or on a cable extending from the boneconduction device 1300. Also, the bone conduction device 1300 comprisesa sound processor (not shown), a vibrating electromagnetic actuatorand/or various other operational components.

More particularly, the sound input element 1326 converts received soundsignals into electrical signals. These electrical signals are processedby the sound processor. The sound processor generates control signalsthat cause the actuator to vibrate. In other words, the actuatorconverts the electrical signals into mechanical force to impartvibrations to a skull bone 1336 of the recipient. The conversion of theelectrical signals into mechanical force can be controlled by inputreceived from a user.

The bone conduction device 1300 further includes a coupling apparatus1340 to attach the bone conduction device 1300 to the recipient. In theillustrated example, the coupling apparatus 1340 is attached to ananchor system (not shown) implanted in the recipient. An example anchorsystem (also referred to as a fixation system) includes a percutaneousabutment fixed to the skull bone 1336. The abutment extends from theskull bone 1336 through muscle 1334, fat 1328 and skin 1332 so that thecoupling apparatus 1340 can be attached thereto. Such a percutaneousabutment provides an attachment location for the coupling apparatus 1340that facilitates efficient transmission of mechanical force. Anotherexample anchor system includes the use of a headband, strap, or otherdevice to hold a vibratory plate (configured to impart vibrations to therecipient's skull) proximate the recipient's skull without the need touse an implanted anchor. In yet another example anchor system, one ormore magnets are implanted beneath the recipient's skin 1332 andmagnetic attraction between the bone conduction device 1300 and themagnets are used to retain the bone conduction device 1300.

Further Example Treatments

In addition to or instead of the use of devices to treat presbycusis,other therapies or treatments can be used, such as pharmaceuticalproducts. For example, a vascular dilation drug can be prescribed. DNAtherapy can be prescribed or recommended as a treatment for inner haircell loss. Or devices which contain pharmaceuticals in a combinationdevice may be prescribed.

As should be appreciated, while particular uses of the technology havebeen illustrated and discussed above, the disclosed technology can beused with a variety of devices in accordance with many examples of thetechnology. The above discussion is not meant to suggest that thedisclosed technology is only suitable for implementation within systemsakin to that illustrated in the figures. In general, additionalconfigurations can be used to practice the processes and systems hereinand/or some aspects described can be excluded without departing from theprocesses and systems disclosed herein.

This disclosure described some aspects of the present technology withreference to the accompanying drawings, in which only some of thepossible aspects were shown. Other aspects can, however, be embodied inmany different forms and should not be construed as limited to theaspects set forth herein. Rather, these aspects were provided so thatthis disclosure was thorough and complete and fully conveyed the scopeof the possible aspects to those skilled in the art.

As should be appreciated, the various aspects (e.g., portions,components, etc.) described with respect to the figures herein are notintended to limit the systems and processes to the particular aspectsdescribed. Accordingly, additional configurations can be used topractice the methods and systems herein and/or some aspects describedcan be excluded without departing from the methods and systems disclosedherein.

Similarly, where steps of a process are disclosed, those steps aredescribed for purposes of illustrating the present methods and systemsand are not intended to limit the disclosure to a particular sequence ofsteps. For example, the steps can be performed in differing order, twoor more steps can be performed concurrently, additional steps can beperformed, and disclosed steps can be excluded without departing fromthe present disclosure. Further, the disclosed processes can berepeated.

Although specific aspects were described herein, the scope of thetechnology is not limited to those specific aspects. One skilled in theart will recognize other aspects or improvements that are within thescope of the present technology. Therefore, the specific structure,acts, or media are disclosed only as illustrative aspects. The scope ofthe technology is defined by the following claims and any equivalentstherein.

What is claimed is:
 1. A method, comprising: measuring a stiffness of abasilar membrane at a region of an inner ear, wherein the measuringincludes: providing a sound wave having a first frequency configured toactivate the region, and a second frequency that is lower than the firstfrequency and is configured to bias the region; and measuring a responseto the provided sound wave.
 2. The method of claim 1, furthercomprising: determining a level of cochlea conductive presbycusis basedon the measured response.
 3. The method of claim 1, further comprising:determining a plurality of presbycusis sub-factors, wherein cochleaconductive presbycusis is one of the plurality of the presbycusissub-factors; and determining contribution of each of the plurality ofpresbycusis sub-factors to overall presbycusis.
 4. The method of claim3, further comprising: performing a treatment action based on themeasured plurality of presbycusis sub-factors.
 5. The method of claim 4,wherein performing the treatment action includes: recommending apharmacological substance, a hearing aid, a bone conduction device, acochlear implant, a hearing aid fitting, or a bone conduction fitting.6. The method of claim 1, further comprising: performing the measuringof stiffness for one or more additional regions of the cochlea.
 7. Themethod of claim 1, wherein the sound wave is a first wave and a secondsound wave, and wherein measuring the stiffness further includes:providing a first sound wave having the first frequency at a firstvolume to the cochlea; measuring a first response to the first soundwave; and selecting the second sound wave such that a measured secondresponse to the second sound wave is within a threshold amount of thefirst response.
 8. The method of claim 1, wherein measuring the responseincludes measuring otoacoustic emissions.
 9. The method of claim 8,wherein measuring otoacoustic emissions includes: receiving a firstotoacoustic emission corresponding to the first frequency; receiving asecond otoacoustic emission corresponding to the second frequency; anddisregarding the second otoacoustic emission.
 10. The method of claim 1,wherein the second frequency is configured to at least one ofconstructively bias the region; or destructively bias the region.
 11. Amethod comprising: providing a first sound wave having a first frequencyat a first volume to a cochlea; measuring a first response to the firstsound wave; providing a second sound wave to the cochlea such that ameasured second response to the second sound wave is within a thresholdamount of the first response, wherein the second sound wave includes:the first frequency at a modified volume relative to the first volume;and a second frequency, lower than the first frequency, at a secondvolume; and determining a stiffness of a basilar membrane of the cochleabased on one or more differences between the first sound wave and thesecond sound wave.
 12. The method of claim 11, wherein providing thesecond sound wave to the cochlea includes: providing the second soundwave to the cochlea; and modifying the second sound wave until ameasured second response to the second sound wave is within thethreshold amount of the first response.
 13. The method of claim 12,wherein modifying the second sound wave until a measured second responseto the second sound wave is within the threshold amount of the firstresponse includes: modifying the modified volume of the first frequency;or modifying the second volume of the second frequency.
 14. The methodof claim 11, wherein the second sound wave includes multiple additionalfrequencies that are lower in frequency than the first frequency. 15.The method of claim 14, wherein the multiple additional frequencies areharmonic.
 16. The method of claim 11, wherein measuring the firstresponse includes measuring the first response with anelectrocochleogram.
 17. The method of claim 11, further comprising:diagnosing a hearing condition of the cochlea based on the stiffness ofthe basilar membrane being above a diagnostic threshold.
 18. The methodof claim 11, wherein the hearing condition is cochlea conductivepresbycusis.
 19. The method of claim 11, wherein determining thestiffness of the basilar membrane of the cochlea based on the one ormore differences between the first sound wave and the second sound waveincludes determining a ratio between the first volume and the secondvolume.
 20. The method of claim 11, wherein at least one of the firstvolume or the modified volume is a volume above an otoacoustic emissionthreshold.
 21. A system comprising: an electroacoustic transducer; aresponse sensor; and one or more processors configured to: provide asound wave using the electroacoustic transducer, the sound wave having:a first frequency configured to activate tissue region; and a secondfrequency configured to bias the tissue region; and measure a responseto the provided sound wave using the response sensor.
 22. The system ofclaim 21, wherein the one or more processors are further configured to:provide a stiffness measurement for a tissue region based on theresponse.
 23. The system of claim 21, wherein the cochlear responsesensor includes one or more electrodes.
 24. The system of claim 21,wherein the response sensor is an electrocochleography monitor.
 25. Thesystem of claim 21, wherein the one or more processors are furtherconfigured to: select the second frequency to constructively bias thetissue region.
 26. The system of claim 21, wherein the one or moreprocessors are further configured to: select the second frequency todestructively bias the tissue region.
 27. The system of claim 21,wherein the one or more processors are further configured to: determinemultiple stiffness measures using a range of frequencies lower than thefirst frequency.
 28. The system of claim 27, wherein the one or moreprocessors are further configured to: provide the multiple stiffnessmeasures as a stiffness spectrogram.
 29. The system of claim 21, whereinthe one or more processors are further configured to: determine cochleaconductive presbycusis based on the response; and recommend a treatmentaction based on the measured cochlea conductive presbycusis.
 30. Thesystem of claim 21, wherein the system includes memory havinginstructions thereon that, when executed, so configure the one or moreprocessors; and wherein the one or more processors are configured tomeasure at least one of strial presbycusis, sensory presbycusis, neuralpresbycusis, or cochlea conductive presbycusis.